In vitro toxicology screening of Centaurea calcitrapa (Asteraceae) extracts, their phenolic profiles, and bioctivity

Abstract

The genus Centaurea is one of the largest genera in the Asteraceae family comprising approximately 400-700 species. Ethnobotanical and ethnopharmacological studies have shown that many Centaurea species have been used in folk medicine for treatment of varios diseases (such as diabetes, to treat fever, high blood pressure diseases, etc.). In the search for potentially bioactive natural plant compounds, special attention needs to be undertaken to identify their toxic or potentially toxic effects. In this regard, a study on the cytotoxicity of C. calcitrapa extracts on MRC-5 cells was performed. The main objective of the present study was to determine and evaluate the bioactivity, phenolic profiles and cytotoxicity of methanol (MeOH), 70 % ethanol (EtOH), ethyl-acetate (EtOAc), 50 % acetone (Me 2 CO), and dichloromethane:methanol (DCM:MeOH, 1:1) C. calcitrapa leaf extracts. The bioactivity against different human pathogenic and phytopathogenic strains was tested using well diffusion method and minimum inhibitory concentration (MIC) assay. A total of 55 phenolic compounds were identified: 30 phenolic acids and their derivatives and 25 flavonoid glycosides and aglycones. The highest cytotoxicity was recorded for EtOAc and Me2CO extracts with the lowest relative and absolute IC50 values between 88 and 102 μg/mL, while the EtOH extract was the least toxic with a predicted relative IC50 value of 1578 μg/mL. Our results indicate that all of the tested extracts, at a non-toxic concentration and simultaneously harmful for human pathogenic and phytopathogenic strains (methicillin-resistant Staphylococcus aureus; Xanthomonas campestris pv. campestris, Erwinia amylovora and Pseudomonas syringae pv. syringae), can be considered natural sources of novel bioactive phytochemicals.